Velocity discriminating time mechanical ordnance fuze

ABSTRACT

A mechanical ordnance fuze having an arming slider held by a timer controlled lock and a catch rod. Axially aligned with the catch rod are a pair of centrifugally opened detents attached to a shaft rotated by a wind driven vane. When the vane is rotating sufficiently fast to open the detents, the catch rod, released by the timer, passes between the detents and clears the arming slider, thereby allowing the slider to arm when released by the lock. Otherwise the catch rod is blocked by the unopened detents and when the timer operates to unlock the slider, it is caught by the catch rod and the fuze remains unarmed.

United States Patent [151 3,677,186 Munach July 18, 1972 [54] VELOCITY DISCRR'IINATING TIIWE MECHANICAL ORDNANCE FUZE Primary Examiner-Benjamin A. Borchelt Assistant Examiner.l. J. Devitt [72] inventor. Arnold S. Munnch, Rockvnlle, Md. Atmrney R S Sciascia and L Cooke [73] Assignee: The United States of America as represented by the Secretary oi the Navy [57] ABSTRACT [22] Filed: Oct. 1, 1969 A mechanical ordnance fuze having an arming slider held by a timer controlled lock and a catch rod. Axially aligned with the 21 A LN 862 700 l 1 pp 0 catch rod are a pair of centrifugally opened detents attached to a shaft rotated by a wind driven vane. When the vane is U.S. 102/83, rotating suflicienfly fast to open the detents the catch rod [51] F42: released by the timer, passes between the detents and clears [58] field of Search ..102/83, 84, 86 the arming Slider thereby allowing the slider to arm when released by the lock. Otherwise the catch rod is blocked by the [56] References cited unopened detents and when the timer operates to unlock the UNITED STATES PATENTS slider, it is caught by the catch rod and the fuze remains unarmed. 2,449,170 9/1948 MacClean et al ..102/84 3,286,632 11/1966 Potts, Jr. et al. 102/84 20 Claims, 7 Drawing Figures 5 Sheets-Sheet l INVENTOR Arnold S. Munach Patent July 18, 1972 Patented July 18, 1972 3 Sheets-Sheet 3 3 Sheets-Sheet 3 III III VELOCITY DISCRIMINATING TIME MECHANICAL ORDNANCE FUZE BACKGROUND OF THE INVENTION This invention relates generally to ordnance fuzes, and more particularly to air burst ordnance fuzes having fail-safe, tamper-proof capabilities.

The character of modern warfare has made it necessary to develop ordnance specially designed for use against various specific classes of targets. This tailoring of ordnance to the target, although improving the efficacy of the associated weapon, has resulted in a proliferation of special purpose ordnance devices, imposing a heavy burden on the personnel who handle the ordnance to learn the special handling techniques and dangers unique to each particular type of device. The inevitable result has been an increasing number of accidental detonations of ordnance during handling because of tampering, carelessness or ignorance. Thus, the safety factor in fuze design has assumed a more critical significance.

In proximity air burst ordnance it is frequently desired that the device be actuated by a mechanical fuze to preclude inactivation by electronic countermeasures and also to reduce cost. Thus, the prior art contains wind vane enabled fuzes, mechanical clockwork actuated fuzes, and, occasionally, a combination of wind vane enabled and clockwork actuated mechanical fuzes. These devices generally have some form of locking pin holding the vane against rotation, removable when the device is released from its delivery vehicle, such as a ship or airplane. While these devices have generally functioned satisfactorily when handled carefully, the danger is always present that the locking pin can be accidentally or deliberately withdrawn and the vane freed for rotation. This danger may have been acceptable when a typical storage area would have but few types of fuzes so that the handling personnel could easily be trained to be sensitive to the danger of a missing locking pin or some other abnormal condition. But modern day ordnance storage areas contain many different types of fuzes: some having vane locking pins and some having none; some requiring such high rates of vane spin and such high torque that the human hand could not spin the vane fast and hard enough to arm the fuze; and some requiring only a very low rate of spin and only a few revolutions before the fuze is armed. With this plethora of fuzes in a typical storage area, it is virtually impossible for the handling personnel to be sufficiently trained to be cognizant of the particular dangers associated with each particular type of fuze.

Therefore, a need has long existed in the ordnance fuze field for an air burst ordnance fuze that is environmentally enabled by a wind stream but will remain unarmed in case of tampering or in the absence of the environmental conditions under which the ordnance device is designed to operate. The prior art is repleat with vane enabled fuzes but for the most part they do not provide the needed tamper-proof security, and those that do, do so only with the use of cumbersome, complicated, unreliable, and expensive mechanisms. Once the vane locking pin has been removed from most fuzes the vanes can be rotated by hand until the fuze is armed and subsequent operation of a timer or impact as by dropping will then detonate the fuze, possibly resulting in a chain detonation of other explosives in storage with a consequent loss of life and destruction of property.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide a mechanical ordnance fuze that functions at a preselected time only when sufficient air speed is present within a fixed time interval following fuze unlocking but otherwise renders itself inoperative, thereby providing protection against premature arming.

Another object of the present invention is to provide a mechanical ordnance fuze having a timed btust capability, the time of which is capable of extremely precise setting.

A further object of this invention is to provide a tamperproof mechanical ordnance fuze having a safe setting capability for shipment and storage of the fuze in which the fuze is positively incapable of being inadvertently armed.

Yet another object of this invention is to provide a tamperproof mechanical ordnance fuze having a timed air burst capability and being highly secure against an inadvertent maladjustment of the time at which the ordnance is set to burst, and in which the timer mechanism is protected against damage during adjustment.

A still further object of this invention is to provide a mechanical ordnance fuze that is capable of adjustable discrimination between air speeds.

Yet another object of this invention is to provide a mechanical ordnance fuze having a wind driven van whose shafi is environmently sealed and locked, prior to deployment but whose rotation in operation is unimpeded.

Another further object of this invention is to provide a mechanical ordnance fuze that remains securely unarmed until the instant the fuze functions.

Still another further object of this invention is to provide a mechanical ordnance fuze having relatively few moving parts, design simplicity and economy of function, and a relatively low production cost.

Briefly, in accordance with one embodiment of this invention, these and other objects are attained by providing a mechanical ordnance fuze having an arming slider restrained from movement to an armed position by a timer controlled catch rod. A passage for the rod is blocked by a mechanism which may be opened by rotation of the vane. The timer and the vane are simultaneously released and if the vane rotates fast enough to open the passage before the timer releases the catch rod then the catch rod will enter the passage clearing the arming slider, and permit the fuze to arm. If, on the other hand, the vane is not rotated sufficiently fast to open the passage then, upon release of the catch rod by the timer, it will be blocked by the passage closing mechanism and will not clear the arming slider, thus retaining the fuze unarmed.

BRIEF DESCRIPTION OF DRAWINGS A more complete appreciation of the invention and its many attendant advantages will develop as the same becomes better understood by reference to the following detailed. description when considered in connection with the accompanying drawings wherein:

FIG. 1 is an elevational view, partly in section of the invention;

FIG. 2 is a sectional elevational view along line 2--2 of FIG.

FIG. 3 is a sectional view along line 3-3 of FIG. 1;

FIG. 4 is a plan view of the underside of the bottom plate of the timer;

FIG. 5 is a sectional view of the timer plate along line 5-5 in FIG. 2;

FIG. 6 is a side elevational view of the window of FIG. 2; and,

FIG. 7 is a plan view of the detent mechanism along line 7- 7 in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings wherein like reference characters designate identical or corresponding parts throughout the several views, and more particularly to FIG. I thereof, the fuze is shown as having a housing 10 with a cylindrical sidewall 12 open at the upper end 14 and closed at the lower end by a bottom wall 16 thereby providing a forwardly opening cavity 18. As best seen in FIGS. 2 and 3, the lower portion of housing 10 has formed therein a transverse bore 20 open and internally threaded at one end thereof to slideably receive a cylindrical arming slider 21 shown in a first, or inert position, and which communicates through an aperture 22 centrally formed in bottom wall 16 with an ordnance device,

such as a bomb, to which the fuze is fixed. A firing pin 24 is threadedly engaged at 26 in the side wall 12 of casing and is sealed at the outside end thereof by O-ring seal 28. The pin 24 protrudes axially into bore 20. The open end of bore is closed by a threaded plug 30 and sealed by an O-ring 32. A central well 34 is formed on the inside of plug 30 to receive a compression coil spring 36 which bears against the rear face 38 of slider 21, urging slider 21 toward its second, or firing position in engagement with firing pin 24.

Referring now more particularly to FIGS. 1 and 3, a guide pin 40 is fixed in casing 10 and fits into a longitudinal slot 42 formed in slider 21 for a purpose which will be explained more fully hereinafter. A shallow longitudinal slot 44 is formed in slider 21 displaced 90 from slot 42 and has rear portion 46 narrowed by the protrusion of a projecting flange 48 into slot 44 and a deep portion 50 extending into a cylindrical axial cavity 52, best seen in FIG. 2, in the rear of slider 20. Opening into axial cavity 52 in arming slider 21 is a coaxial detonator cavity 54 holding a detonator 56. Communicating therewith is a transverse cavity 58 perpendicular thereto and containing a transfer explosive lead 60.

Referring now to FIG. 2, an aperture 62 is formed in housing 10 to communicate between cavity 18 and bore 20 and slideably receive a catch rod 64 which extends through aperture 62, into bore 20, through deep portion 50 of slot 44 and into axial cavity 52. Another aperture 68 is formed in housing 10 which communicates between cavity 18 and transverse bore 20 to rotatably receive a locking shaft 70. The lower portion of locking shaft 70 has formed therein a short semicylindrical cut 72 leaving a semicylindrical stud 73 protruding into bore 20 and slot 44 as best seen in FIGS. 2 and 4. A firing lever 74 is keyed to shaft 70 immediately above aperture 68.

A timer 76, best seen in FIGS. 1 and 2 having parallelspaced upper support plates 78 and 80 and parallel-spaced lower support plates 82 and 84 is secured to bottom 16 of housing 10 as by screws 86. An inverted cup-shaped housing 88 contains a spiral main spring connected to a hollow arbor 92 which, in turn, drives a gear amplification and escapement mechanism 90 which acts to limit the rate of rotation of the timer. Keyed to arbor 92 is a disc 94 from which radially extends an arm 96 having a downwardly depending foot 98. A pin 100 is slidably disposed and environmentally sealed in wall 12 of housing 10 by O-ring 101, to protrude into cavity 18 and block the angular passage of foot 98 to thereby prevent the rotation of arbor 92 and restrain the operation of timer 76 until pin 100 is removed. Diametrically opposed to arm 96 is a radially extending circular sector 1 10 having an angular extent of approximately to 35. Also keyed to arbor 92 is a disc 112 having four equally spaced friction arms 114 extending outwardly and downwardly therefrom. Friction arms 114 press against the upper face of a timing disc 116 which is disposed on arbor 92 for rotation relative thereto, thereby providing a strong frictional force connection between arbor 92 and disc 116 so that disc 116 normally rotates with arbor 92. Adjacent its outside edge 117, timing disc 116 carried a low upstanding cylindrical wall 118 having numbers such for example as l to 9.5 and a scale in one-tenth intervals inscribed upon the outside face thereof. A radial firing slot 120 is cut into wall 118 and also into timing disc 116 as best seen in FIGS. 2 and 5. A set of gear teeth 122 are formed on the upper edge of cylindrical wall 118 and extend completely around the circular extent thereof.

A shaft 124, shown in FIG. 2 and shown broken in FIG. 1 for clarity, is rotatably journalled between support plates 82 and 84 and extends below plate 84. Affixed to shaft 124 above plate 84 is an L-shaped lever 126 having a vertical upstanding drop leaf 128, and below plate 84, shaft 124 has affixed thereto a release lever 130, shown foreshortened in FIG. 2 because of the angle. A torsion spring 132 coiled about and coaxial with shaft 124 urges counterclockwise rotation of shaft 124 and the levers 126 and 130 affixed thereto so that, as seen in FIGS. 1, 2 and 5, drop leaf 128 is biased radially inward to press against the outside edge of sector 110. Im-

mediately above lever 130, a transverse slot 133 is cut half way into shaft 124 which, upon rotation of shaft 124, provides a clearance for the tip 134 of firing lever 74 thus freeing lever 74 for rotation.

A cup 140 is afiixed to the upper end of catch rod 64 and a volute coil spring 142 bears against the closed lower end 144 of cup 140, urging cup 140 and rod 64 upwardly. A safety indicator 136 is affixed to its catch rod 64 immediately above aperture 62 and provides, at the attachment thereof to rod 64, a shoulder 138, which is engaged by the end of lever 130 to restrain upward movement of rod 64. When arbor 92 rotates sector clockwise as indicated by arrow 147 in FIGS. 2 and 5 out of engagement with drop leaf 128 thus permitting spring 132 to rotate lever 126 inwardly until drop leaf 128 abuts against the outside edge 117 of timing disc 116, shaft 124 will rotate counterclockwise with lever 126, and lever will rotate counterclockwise an equal angular rotation, thus moving out of engagement with shoulder 138 and permitting the upward movement of rod 64 under the action of volute coil spring 142.

As the timer continues to run, rotating timing disc 116 and upstanding cylindrical wall 118, the firing slot 120 is carried around until it is presented to drop leaf 128. At this time, spring 132 will rotate lever 126 and drop leaf 128 into firing slot 120, thereby permitting the counterclockwise rotation of shaft 124. As best seen in FIG. 4, the counterclockwise rotation of shaft 124 (which in FIG. 4 appears as clockwise rotation because of the orientation of the view) will present slot 133 to the tip 134 of firing lever 74 thus freeing firing lever 74 for clockwise rotation, as it appears in FIG. 4, of lever 74. As seen in FIG. 3, the upper edge of semicylindrical stud 73 of shaft 70 is loaded by the projecting flange 48, and when shaft 70 is freed for rotation by the slot 133 being presented to the tip 134 of firing lever 74, the shaft will rotate under the influence of compression spring 36 and the arming slider 21 will be freed to slide axially into firing pin 24 as best seen in FIG. 2. Then, the detonator 56 in cavity 54 will be punctured by the pointed end of firing pin 24 and will detonate. At the same instant, the cavity 58 will be aligned with aperture 22 and the blast from the transfer explosive lead 60 will pass through aperture 22 into and initiating the ordnance device to which the fuze is attached.

To provide against the contingency of the gear amplification and escapement mechanism 90 failing and allowing the timing disc 116 to spin around unchecked and thereby presenting the possibility of a virtually instantaneous detonation, a runaway check is provided, as best seen in FIG. 5, by forming a small tab 145 on the inside edge of slot 120. The speed of a runaway timing disc 116 is such that the drop leaf 128 will be caught by the shoulder 143 formed by tab 145 and prevented from entering fully into slot 120. Thus, locking shaft 70 will not rotate sufficiently to release slider 21 and the fuze will remain safe.

The time between the unlocking of timer 76 and the dropping of drop leaf 128 into firing slot 120 is variable by allowing the radial position of timing disc 116 to be adjustable with respect to disc 94. Thus, it is possible to rotate disc 116 with respect to arbor 92 by holding arbor 92 fixed and forcing the rotation of the disc 116 against the frictional force exerted by the lower edge of arms 114.

This rotation is accomplished externally of the casing 10 by means of a timer setting mechanism 146 as best seen in FIG. 2. Timer setting mechanism 146 is mounted in a cylindrical bore 148 in a cylindrical boss 150 formed on casing 10. A pinion gear 152 having a shank 154 cut by a radial slot 156 and a central bore 158 is slideably mounted upon a setting shaft 160. A pin 162 is fixed in a lateral hole drilled through setting shaft and extends beyond the peripheral dimension of shaft 160 to ride in the slot 156 of shank 154. Thus, rotation of shaft 160 will, through the agency of pin 162, rotate pinion gear 152. A weak compression spring 164 is coiled about shaft 160 and bears against the outside face of shank 154 urging pinion gear 152 radially inward against a stop 166 at the end of shaft 160.

The outside end of setting shaft 160 has an enlarged head 168 with a peripheral groove 170 therearound and a screwdriver slot 172 is cut into the outside face thereof. A strong compression spring 174 urges shaft 160 outwardly to the full extent permittedby retaining ring 176. A sealing ring 178 seated within groove 170 provides an environmental seal between the outside of the fuze and cavity 18.

In operation the timer setting mechanism is pushed inwardly by a screwdriver engaged in slot 172 in the outside face of the enlarged head 168. If pinion gear 152 does not immediately mesh with gear teeth 122 on the top of upstanding wall 118 then shaft 160 will slide axially through bore 158 in pinion gear 152 and the weak compression spring 164 will compress. Thus, considerable force is necessary to compress spring 174 thereby precluding accidental changes of timer setting, but this large force will not be transmitted to the sensitive mechanism of the timer because the only force exerted through the cylindrical wall 118 to the timer is that of weak spring 164, thus the timer will not be damaged. When the timer setting mechanism has been pushed inwardly and pinion gear 152 is not in mesh with gear teeth 122 on top of upstanding wall 118, the shaft 160 of timer setting mechanism 146 is merely rotated and the pinion gear 152 will immediately mesh with teeth 122 on top of upstanding wall 118 and move under the action of spring 164 inwardly into full engagement with teeth 122.

A window 180 is set into wall 12 of fuze casing 10. A pointer 182 is secured to the underside of timer support plate 82 adjacent to upstanding wall 118 and in line with window 180. Window 180 permits the visual alignment of pointer 182 with the desired timer setting numeral inscribed on the outside face of upstanding wall 118 thereby allowing a continual visual check on the timer setting. Window 180 includes a flanged ring or eyelet 184 into which a lens 186 is cast. Eyelet 184 rests on a shoulder in an aperture 188 cut through side wall 12 of fuze housing and encloses and compresses a sealing ring 190. Window 180 is retained in position by a spring retaining ring 192 which fits into a circumferential groove 194 cut into the wall of aperture 188.

Safety indicator 136 is interposed between window 180 and pointer 182. The upper end of indicator 136 has formed therethrough a D-shaped hole 196, as best shown in FIG. 6, and immediately therebelow the letter A" is painted. When rod 64 is retained in its lowermost position by the engagement of lever 130 with shoulder 138, as illustrated in FIG. 2, the D- shaped hole is aligned between window 180 and pointer 182 and wall 1 18 is visible through the hole. When rod 64 has been released by lever 130 and indicator 136 has moved upward with rod 64, then the letter A on indicator 136 will be aligned with window 180 and wall 118 will be obscured. At this point anyone looking through window 180 will be readily able to see that rod 64 has been released.

During shipment and storage, it is desirable that the fuze be rendered inactive so that under all conditions, even those under which the fuze is designed to arm, the fuze will remain absolutely safe and incapable of arming. This condition is achieved simply in this fuze by aligning the word safe on wall 118 with pointer 182, as shown in FIG. 5. In this circumstance, sector 110 is aligned immediately beneath firing slot 120 and therefore absolutely precludes the rotation of drop leaf 128 into firing slot 120. In this position, even the freak occurrence of environmental conditions and defeat of all the other safety devices of the fuze will not suffice to cause the fuze to arm. This feature, in conjunction with the design of the setting mechanism 146 which precludes accidental changes in setting, provides a safety combination that is virtually foolproof.

As more clearly seen in FIGS. 1 and 7, a pair of spring biased detents 198 and 198' are disposed in a detent case 200 adjacent and facing the open, forward facing end 141 of cup 140. Detents 198 and 198' are rotatably mounted on pivot pins 210 and 210 fixed in detent case 200 and are held in the closed position illustrated in FIG. 7 by coiled springs 212 and 212'. Raised half cylinders 214 and 214' are disposed on the inside edges of detents 198 and 198', respectively, so that when in closed position the two half cylinders form a full cylinder. The inside diameter of cup 140 is somewhat larger than the outside diameter of the cylinder formed by raised half cylinders 214 and 214' so that cup 140 will fit over the cylinder. Thus, if rod 64 is released before detents 198 and 198 have been centrifugally opened against the action of their biasing springs 212 and 212' the cup will capture the cylinder 214 and 214' and thereby prevents subsequent opening of detents 198 and 198'. If however, the detents have opened be fore rod 64 is released, rod 64 is free to move upward between the open detents.

As better shown in FIG. 1, detent housing 200 is secured to a hollow shaft 216 as by threading at 217. I-Iollow shaft 216 is rotatably supported by ball bearings 218 mounted in an axial bore 220 formed in a support block 222. Support block 222 fits snugly within and is secured to walls 12 of casing 10 by pins or screws, not shown, and is environmentally sealed therein by means of an O-ring 224. Support block 222 has downwardly depending legs 226 which bear against timer support plate 82 and assist screws 86 in holding timer 76 rigidly in place. The forward extremity 228 of hollow shaft 216 is reduced in diameter and has an axial bore 230 of which the forward part is threaded at 232 to receive a screw 234 which, in turn, secures a wind vane 236 to the end of the reduced portion 228 of hollow shaft 216.

A transverse bore 238 is formed in support block 222 and is aligned with another transverse bore 240 in the reduced portion 228 of hollow shaft 216 to slideably receive an arming pin 242. Transverse bore 238 has an enlarged diameter portion 244 and arming pin 242 has an enlarged diameter portion 246 of approximately even diameter with enlarged portion 244 of transverse bore 238. A compression spring 248 is disposed between the inside face 250 of enlarged portion 246 of arming pin 242 and the shoulder 252 formed at the junction of enlarged portion 244 and the narrow portion of transverse bore 238.

Disposed within axial bore 230 in reduced portion 228 of hollow shaft 216 is a compression spring 254 which bears against the lower face 256 of screw 234 and the upper face of a cylindrical pellet 258 which fits loosely within bore 230. Compression spring 254 exerts an upward force on screw 234 and thereby on the entire shaft 216. This upward force causes a flange 260 on the wide diameter portion of hollow shaft 216 to engage and compress an O-ring 262 and thereby provide an environmental seal between the exterior of the fuze and cavity 15.

A cylindrical shroud 264 is fitted over support block 222 abutting against the upper edge 14 of cylindrical wall 12 and surrounds wind vane 236 to protect it from damage. Three equally spaced air escape channels 266 communicate between the open forward face of shroud 264 and the lateral outside surface thereof to provide unrestricted air flow across vane 236.

A cylindrical knob 268 is formed on the outside of cylindrical wall 12 and has a pair of spaced lateral holes drilled therein which contain a fixed retaining pin 270 and a removable safety pin 272. A pair of compression springs 274 bears against a washer 275 and against the inside face of an enlarged head 276 on pin urging pin 100 radially outward. The force and stroke of compression springs 274 are balanced with the force and stroke of compression spring 248 so that the outward forces exerted by these compression springs are approximately equal. A bracket 278 is mounted over cylindrical knob 268 and is held in place thereon by the engagement of safety pin 272 with the inner edge of a slot 280 cut in both sides 281 of bracket 278. When safety pin 272 and lanyard 282 are removed, the balanced force of compression springs 274 and 248 will push pins 100 and 242 outward at approximately the same rate, pushing bracket 278 outward until fixed retaining pin 270 engages the inward end of slot 280. At its outermost position, bracket 278 will be approximately parallel with the longitudinal axis of the fuze and the pins 100 and 242 will remain clear of foot 98 and shaft 228 respectively.

In operation an ordnance device, such as a bomb, contain ing the fuze is loaded on the delivery aircraft and a lanyard 282 extending through a hole bored in cylindrical knob 268 is attached to the bomb rack. Safety pin 272 is then removed and bracket 278 is retained in position by lanyard 282. When the bomb is released from the aircraft the lanyard 282 is withdrawn from the hole through cylindrical knob 268 and bracket 278 is free to move radially outward under the action of coil springs 274 and 248. As the bracket 278 moves radially outward, pins 100 and 242 simultaneously move radially outward with bracket 278 thereby simultaneously releasing vane 236 and timer 76 for operation. Retaining pin 270 prevents the complete escape of bracket 278 and pins 242 and 100 to prevent damage to other aircraft in the vicinity or even the delivery aircraft by high speed encounter with small pieces of loose hardware. When pin 242 is removed from transverse bore 240 the dynamic air pressure acting on vane 236 will move shaft 216 inwardly, shifting flange 260 rearwardly out of engagement with seal 262 and seating a bevel edge 284 on shaft 216 into engagement with the upper ring of ball bearings 218. Since there is no load on hollow shaft 216, the wind acting on the vane 236 will very quickly increase the angular velocity thereof and the centrifugal force acting on detents 198 and 198' will cause them to open. Biasing springs 212 can be chosen of any desired compressive force to enable an adjustment to be made as to the wind velocity at which the detents are desired to be opened.

Simultaneously with the release of wind vane 236, the timer 76 is unlocked by the withdrawal of pin 100 from engagement with foot 98 on arm 96 of disc 94, and arbor 92 is now free to rotate under the action of the spiral main spring at a rate controlled by the gear amplification and escapement mechanism 90. As the main shaft rotates it carries with it disc 94 and circular sector 110 which rotates out of engagement with drop leaf 128, thus permitting the radially inward rotation of drop leaf 128 under the action of spring 132 until it abuts against the outside edge 117 of timing disc 116. This counterclockwise rotation of drop leaf 128 is accompanied by an equal angular rotation of release lever 130, as better seen in FIG. 4, which disengages the end of lever 130 from shoulder 138 and thereby permits the upward movement of rod 64 under the action of volute compression spring 142. As disc 116 continues to rotate, slot 120 is eventually presented to drop leaf 128, at which time drop leaf 128 will be rotated under the action of spring 132 fully into slot 120 thereby rotating shaft 124 and presenting slot 133 to the tip 134 of firing lever 74, clearing the same for rotation through slot 133. Shaft 70 will be rotated by spring 36 acting through flange 48 and will present the narrow dimension of stud 73 to the reduced portion 46 of slot 44, thereby clearing arming slider 21 to slide in bore 20, guided by pin 40 riding in slot 42.

If the angular velocity of the vane 236 is insufficient to open detents 198 by the time rod 64 is released, cup 140 on the end of rod 64 will capture the raised cylinder 214 and will be blocked from further upward movement by closed detents 198. in this position cannelure 66 on the bottom of rod 64 is aligned with the inner edge 286 of the deep portion 50 of slot 44. Thus, when the timer runs out and drop leaf 128 is rotated into slot 120, the arming slider 21 will be released for sliding movement in bore 20 but edge 286 will be caught and engaged by cannelure 66, and slider 21 will be permanently prevented from sliding into engagement with firing pin 24. Even should detents 98 subsequently open, the fuze will remain in safe condition because coiled volute spring 142 is not sufi'iciently strong to force cannelure 66 on rod 64 upward out of engagement with edge 286. Thus, the fuze will be permanently disarmed. If, however, detents 198 have opened by the time rod 64 is released, rod 64 will move upward between detents 198 fully clear of arming slider 21. When timer 76 has rotated timing disc 116 to present slot 120 to drop leaf 128, locking shaft 70 will release arming slider 21 and spring 36 will push slider 21 forcefully into engagement with firing pin 24 and the fuze will function.

Obviously, numerous variations and modifications of the above described best mode or preferred embodiment of the invention defined by the appended claims may be made.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A mechanical ordnance fuze comprising: a housing; a vane journaled in said housing for rotation by an airstream; a timer disposed in said housing; arming means shiftable between a first position and a second position; catch means controlled by said timer and disposed to prevent said shift of said arming means, to said second position thereof, and releasable by said timer to move clear of said arming means for permitting said shift of said arming means to said second position thereof; means controlled by said vane for blocking said movement of said catch means clear of said arming means; said blocking means operable, responsive to a predetermined angular velocity of said rotatable vane, to permit movement of said catch means clear of said arming means. 2. The fuze defined in claim 1 further comprising: locking means controlled by said timer and disposed to lock said arming means in said first position, and releasable by said timer to release said arming means for shift thereof to said second position. 3. The fuze defined in claim 2 further comprising: a timing disc rotated by said timer and having a slot formed in the periphery thereof; a drop leaf movably mounted adjacent said timing disc; leaf biasing means acting on said drop leaf for urging said movement thereof toward said timing disc and into said slot; releasing means operatively connected to said drop leaf and movable therewith for releasing said locking means upon movement of said drop leaf under the action of said biasing means into said slot. 4. The fuze defined in claim 3 further comprising: means rotatable with said timing disc and also shiftable relative thereto to a position blocking said slot for preventing said movement of said drop leaf into said slot. 5. The fuze defined in claim 3 further comprising: means for adjusting the angular orientation of said disc with respect to said drop leaf whereby the time between the starting of said timer and said movement of said drop leaf into said slot may be adjusted. 6. The fuze defined in claim 5 further comprising: a window in said housing positioned opposite said disc; an indicator connected to said catch means and movable therewith to interpose between said window and said disc; whereby said window permits visual inspection of the orientation of said disc and also of the position of said indicator and thereby of said catch means. 7. The fuze defined in claim 6 wherein said adjusting means comprises:

a shaft mounted adjacent said disc for rotational and translational motion, shaft biasing means for biasing said shaft against said translational movement toward said disc; drive means mounted on said shaft for engaging and driving said disc, said drive means being shiftable axially relative to said shaft; means for biasing said drive means axially along said shaft into engagement with said disc; whereby said shaft may be moved against the force of said shaft biasing means to bring said drive means into engagement with said disc and said drive means may shift axially along said shaft against the force of said drive means biasing means to limit the translational force exerted on said disc via said shaft to the force exerted by said drive means biasing means.

8. The fuze defined in claim 3 further comprising:

a lever operatively connected to said drop leaf and movable therewith;

said lever engaging said catch means to prevent said movement thereof clear of said arming means, and upon said movement of said lever, releasing said catch means to move clear of said arming means;

means rotated by said timer with said timing disc for engaging and holding said drop leaf against said movement thereof, and upon rotation of said engaging means by said timer, releasing said drop leaf to move under the action of said biasing means whereby said lever connected to said drop leaf will move therewith and release said catch means to move clear of said arming means.

9. The fuze defined in claim 8 wherein:

said engaging means is adapted to be moved relative to said disc to a position adjacent to said slot whereby said movement of said drop leaf into said slot is prevented.

10. The fuze defined in claim 1 further comprising:

a drop leaf movably mounted in said housing;

biasing means acting upon said drop leaf for urging said movement thereof;

a lever operatively connected to said drop leaf and movable therewith;

said lever engaging said catch means to prevent said movement thereof clear of said arming means, and upon said movement of said lever, releasing said catch means to move clear of said arming means;

means rotated by said timer for engaging and holding said drop leaf against said movement thereof, and upon rotation thereof by said timer, releasing said drop leaf to move under the action of said biasing means whereby said lever connected to said drop leaf will move therewith and release said catch means to move clear of said arming means.

1 1. The fuze defined in claim 10 further comprising:

a window in said housing positioned opposite said disc;

an indicator connected to said catch means and movable therewith to interpose between said window and said disc;

whereby said window permits visual inspection of the orientation of said disc and also of the position of said indicator and thereby of said catch means.

12. The fuze defined in claim 11 wherein:

said indicator is interposed between said window and said disc in all positions of said catch means;

said indicator has formed therethrough an aperture which is aligned between said window and said disc when said catch means is disposed to prevent said shift of said arming means to said second position thereof, but release of said catch means to move clear of said arming means will move said indicator and carry said aperture out of alignment between said window and said disc,

whereby said disc is visible through said window and said aperture when said catch means is disposed to prevent said shift of said arming means, but said disc is obscured by said indicator when said catch means has moved clear of said arming means to permit said shift thereof to said second position.

13. The fuze defined in claim 1 wherein said blocking means comprises:

a vane shaft to which said vane is affixed;

centrifugally opened detents rotated by said vane Shah and, in closed position, disposed to block said movement of said catch means and, in open position, disposed to permit movement of said catch means.

14. The fuze defined in claim 13 wherein:

said catch means comprises a rod having a cup connected t one end thereof having an open end facing said detents;

said detents have projecting means formed thereon adapted to be enclosed by said cup to prevent said opening of said detents should said rod be released and said cup capture and enclose said projecting means before said detents be centrifugally opened by said rotating vane.

15. The fuze defined in claim 14 further comprising:

a drop leaf movably mounted in said housing;

biasing means acting upon said drop leaf for urging said movement thereof;

a lever operatively connected to said drop leaf and movable therewith;

said lever engaging said catch means to prevent said movement thereof clear of said arming means, and upon said movement of said lever, releasing said catch means to move clear of said arming means;

means rotated by said timer for engaging and holding said drop leaf against said movement thereof, and upon rotation thereof by said timer, releasing said drop leaf to move under the action of said biasing means whereby said lever connected to said drop leaf will move therewith and release said catch means to move clear of said arming means.

16. The fuze defined in claim 15 further comprising:

a window in said housing positioned opposite said disc;

an indicator connected to said catch means and movable therewith to interpose between said window and said disc;

whereby said window permits visual inspection of the orientation of said disc and also of the position of said indicator and thereby of said catch means.

17. The fuze defined in claim 13 further comprising:

a pair of pins slideably disposed in said housing, a respective one of each extending laterally into said vane shaft and into said timer respectively to prevent the rotation of said shaft and said timer respectively;

pin biasing means for urging said pins out of engagement with said vane shaft and said timer respectively;

a bracket releasably holding said pins in said housing and in engagement with said vane shaft and said timer respectively;

whereby release of said bracket simultaneously releases both of said pins for withdrawal by said biasing means from engagement from said vane shaft and said timer respectively to permit the simultaneous start of rotation of said vane and said timer.

18. The fuze defined in claim 17 further comprising:

sealing means between said vane shaft and said housing,

bearings mounting said shaft for rotation and also for axial shifting,

said pin extending laterally into said vane shaft holding said vane shaft axially forward in said bearings and compressing said sealing means between said vane shaft and said housing to effect an environmental seal;

whereby when said pin is withdrawn from said vane shaft, said vane shaft is free to shift axially rearward in said bearings out of contact with said seal to permit friction free rotation of said vane shaft.

19. The fuze defined in claim 13 further comprising:

bearings mounted in said housing supporting said vane shaft for rotation and for limited axial shifting;

a shoulder formed on said vane shaft;

sealing means disposed between said shoulder and said housing;

means for releasably holding said vane shaft axially forward to compress said sealing means between said shoulder and said housing to effect an environmental seal; and

means for releasing said vane shaft for axial shifting rearward to break said environmental seal and permit free rotation of said vane shaft.

20. The fuze defined in claim 2 wherein said arming means comprises:

a slider engaged and restrained by said locking means and having formed therein an axial cavity and, communicating therewith, a transverse cavity;

a detonator contained in said axial cavity;

a transfer explosive lead contained in said transverse cavity;

a firing pin fixed in said housing and aligned with said axial cavity;

biasing means pushes said slider into engagement with said firing pin to initiate said detonator which, in turn, in-

itiates said transfer explosive lead which fires through said aperture to initiate an ordnance device. 

1. A mechanical ordnance fuze comprising: a housing; a vane journaled in said housing for rotation by an airstream; a timer disposed in said housing; arming means shiftable between a first position and a second position; catch means controlled by said timer and disposed to prevent said shift of said arming means to said second position thereof, and releasable by said timer to move clear of said arming means for permitting said shift of said arming means to said second position thereof; means controlled by said vane for blocking said movement of said catch means clear of said arming means; said blocking means operable, responsive to a predetermined angular velocity of said rotatable vane, to permit movement of said catch means clear of said arming means.
 2. The fuze defined in claim 1 further comprising: locking means controlled by said timer and disposed to lock said arming means in said first position, and releasable by said timer to release said arming means for shift thereof to said second position.
 3. The fuze defined in claim 2 further comprising: a timing disc rotated by said timer and having a slot formed in the periphery thereof; a drop leaf movably mounted adjacent said timing disc; leaf biasing means acting on said drop leaf for urging said movement thereof toward said timing disc and into said slot; releasing means operatively connected to said drop leaf and movable therewith for releasing said locking means upon movement of said drop leaf under the action of said biasing means into said slot.
 4. The fuze defined in claim 3 further comprising: means rotatable with said timing disc and also shiftable relative thereto to a position blocking said slot for preventing said movement of said drop leaf into said slot.
 5. The fuze defined in claim 3 further comprising: means for adjusting the angular orientation of said disc with respect to said drop leaf whereby the time between the starting of said timer and said movement of said drop leaf into said slot may be adjusted.
 6. The fuze defined in claim 5 further comprising: a window in said housing positioned opposite said disc; an indicator connected to said catch means and movable therewith to interpose between said window and said disc; whereby said window permits visual inspection of the orientation of said disc and also of the position of said indicator and thereby of said catch means.
 7. The fuze defined in claim 6 wherein said adjusting means comprises: a shaft mounted adjacent said disc for rotational and translational motion, shaft biasing means for biasing said shaft against said translational movement toward said disc; drive means mounted on said shaft for engaging and driving said disc, said drive means being shiftable axially relative to said shaft; means for biasing said drive means axially along said shaft into engagement with said disc; whereby said shaft may be moved against the force of said shaft biasing means to bring said drive means into engagement with said disc and said drive means may shift axially along said shaft against the force of said drive means biasing means to limit the translational force exerted on said disc via said shaft to the force exerted by said drive means biasing means.
 8. The fuze defined in claim 3 further comprising: a lever operatively connected to said drop leaf and movable therewith; said lever engaging said catch means to prevent said movement thereof clear of said arming means, and upon said movement of said lever, releasing said catch means to move clear of said arming means; means rotated by said timer with said timing disc for engaging and holding said drop leaf against said movement thereof, and upon rotation of said engaging means by said timer, releasing said drop leaf to move under the action of said biasing means whereby said lever connected to said drop leaf will move therewith and release said catch means to move clear of said arming means.
 9. The fuze defined in claim 8 wherein: said engaging means is adapted to be moved relative to said disc to a position adjacent to said slot whereby said movement of said drop leaf into said slot is prevented.
 10. The fuze defined in claim 1 further comprising: a drop leaf movably mounted in said housing; biasing means acting upon said drop leaf for urging said movement thereof; a lever operatively connected to said drop leaf and movable therewith; said lever engaging said catch means to prevent said movement thereof clear of said arming means, and upon said movement of said lever, releasing said catch means to move clear of said arming means; means rotated by said timer for engaging and holding said drop leaf against said movement thereof, and upon rotation thereof by said timer, releasing said drop leaf to move under the action of said biasing means whereby said lever connected to said drop leaf will move therewith and release said catch means to move clear of said arming means.
 11. The fuze defined in claim 10 further comprising: a window in said housing positioned opposite said disc; an indicator connected to said catch means and movable therewith to interpose between said window and said disc; whereby said window permits visual inspection of the orientation of said disc and also of the position of said indicator and thereby of said catch means.
 12. The fuze defined in claim 11 wherein: said indicator is interposed between said window and said disc in all positions of said catch means; said indicator has formed therethrough an aperture which is aligned between said window and said disc when said catch means is disposed to prevent said shift of said arming means to said second position thereof, but release of said catch means to move clear of said arming means will move said indicator and carry said aperture out of alignment between said window and said disc, whereby said disc is visible through said window and said aperture when said catch means is disposed to prevent said shift of said arming means, but said disc is obscured by said indicator when said catch means has moved clear of said arming means to permit said shift thereof to said second position.
 13. The fuze defined in claim 1 wherein said blocking means comprises: a vane shaft to which said vane is affixed; centrifugally opened detents rotated by said vane shaft and, in closed position, disposed to block said movement of said catch means and, in open position, disposed to permit movement of said catch means.
 14. The fuze defined in claim 13 wherein: said catch means comprises a rod having a cup connected to one end thereof having an open end facing said detents; said detents have projecting means formed thereon adapted to be enclosed by said cup to prevent said opening of said detents should said rod be released and said cup capture and enclose said projecting means before said detents be centrifugally opened by said rotating vane.
 15. The fuze defined in claim 14 further comprising: a drop leaf movably mounted in said housing; biasing means acting upon said drop leaf for urging said movement thereof; a lever operatively connected to said drop leaf and movable therewith; said lever engaging said catch means to prevent said movement thereof clear of said arming means, and upon said movement of said lever, releasing said catch means to move clear of said arming means; means rotated by said timer for engaging and holding said drop leaf against said movement thereof, and upon rotation thereof by said timer, releasing said drop leaf to move under the action of said biasing means whereby said lever connected to said drop leaf will move therewith and release said catch means to move clear of said arming means.
 16. The fuze defined in claim 15 further comprising: a window in said housing positioned opposite said disc; an indicator connected to said catch means and movable therewith to interpose between said window and said disc; whereby said window permits visual inspection of the orientation of said disc and also of the position of said indicator and thereby of said catch means.
 17. The fuze defined in claim 13 further comprising: a pair of pins slideably disposed in said housing, a respective one of each extending laterally into said vane shaft and into said timer respectively to prevent the rotation of said shaft and said timer respectively; pin biasing means for urging said pins out of engagement with said vane shaft and said timer respectively; a bracket releasably holding said pins in said housing and in engagement with said vane shaft and said timer respectively; whereby release of said bracket simultaneously releases both of said pins for withdrawal by said biasing means from engagement from said vane shaft and said timer respectively to permit the simultaneous start of rotation of said vane and said timer.
 18. The fuze defined in claim 17 further comprising: sealing means between said vane shaft and said housing, bearings mounting said shaft for rotation and also for axial shifting, said pin extending laterally into said vane shaft holding said vanE shaft axially forward in said bearings and compressing said sealing means between said vane shaft and said housing to effect an environmental seal; whereby when said pin is withdrawn from said vane shaft, said vane shaft is free to shift axially rearward in said bearings out of contact with said seal to permit friction free rotation of said vane shaft.
 19. The fuze defined in claim 13 further comprising: bearings mounted in said housing supporting said vane shaft for rotation and for limited axial shifting; a shoulder formed on said vane shaft; sealing means disposed between said shoulder and said housing; means for releasably holding said vane shaft axially forward to compress said sealing means between said shoulder and said housing to effect an environmental seal; and means for releasing said vane shaft for axial shifting rearward to break said environmental seal and permit free rotation of said vane shaft.
 20. The fuze defined in claim 2 wherein said arming means comprises: a slider engaged and restrained by said locking means and having formed therein an axial cavity and, communicating therewith, a transverse cavity; a detonator contained in said axial cavity; a transfer explosive lead contained in said transverse cavity; a firing pin fixed in said housing and aligned with said axial cavity; biasing means engaged with said slider for biasing said slider toward said firing pin; said housing having formed therein an aperture aligned with said transverse cavity when said slider is in said second position, whereby when said locking means releases said slider said biasing means pushes said slider into engagement with said firing pin to initiate said detonator which, in turn, initiates said transfer explosive lead which fires through said aperture to initiate an ordnance device. 